With a large number of power electronics devices connected to the power grid
there are problems
such as inertia and damping decreasing. To improve the frequency stability and power quality of the unbalanced grid
this paper proposes a flexible compensation control strategy of unbalanced voltage based on virtual synchronous generator (VSG). When the frequency of the grid is oscillating
VSG can provide active power support to enhance the stability of power system. By using the feed-forward compensation control of negative sequence voltage
it can restrain the unbalanced voltage at the point the of common coupling and improve the power quality. By building the model of VSG under unbalanced grid
this paper proposes a suppression strategy of unbalanced voltage by using the voltage feed-forward compensation. Then
the performance of voltage feed-forward compensation strategy is analyzed and the compensation coefficient setting method of the unbalanced voltage is studied. The method can realize flexible control
which changes the compensation coefficient automatically according to the goal of voltage unbalanced factor and the remaining capacity of instrument. Finally
simulation results validate the correctness and effectiveness of proposed control strategy.